Antonyms for the word "are overjoyed" include feeling sad, unhappy, disappointed, dejected, and downcast. When someone is underwhelmed or unimpressed, they may feel indifferent or apathetic. In some cases, people can feel discouraged, discontented or frustrated. When things do not go as planned, people may feel disheartened or disillusioned. Another antonym that could be used is dispirited, which describes someone who feels discouraged by a negative situation or outcome. Overall, there are various words that describe emotions that are opposite to being overjoyed, and they can help to convey different shades and nuances of feelings.